Greek Translation

I would like to translate the administrator language and the language in the site for users in Greek language. I'm new in Joomla and of course in Joomshopping. I found some .php files in administrator's directoty in com_jshopping-->lang -->en-GB.php and in the cmponents directory --> com_jshopping --> en-GB.php. I supose that I sould translate these files but after that in which way I can install it in Joomla and Joomshopping component.

Thank you in advance for your help and I'm waiting for your answer soon.

Dear dimitri i have the translation allready done....could you please help ...what i have to do...sent them to the site administrators (support@webdesigner-profi.de) to make them work?
But there a differnt betweeen languages files at Component Joomshopping 2.9.1 and Component Joomshopping 3.2.1...????

Dear webmaster...thanks for the quick respones....but could you please check the zip file..because i try to install it and i take this ''Error.The pakage is not include the file XML''.
Whats going wrong?
Do you think that i do something wrong?
Please see this issue...

Sorry for the delay to answer. Thank for your answer about translation. I'll try to install it on Monday and if I have any problem I'll write you for help. Thank you very much and sorry for the delay again.